Reciprocatory drive for machine tools



Get. 4, 1949. K. F. GALLIMORE 2,433,535

I 'RECIPROCATORY DRIVE FOR MACHINE TOOLS Filed July 31, 1944 2Sheets-Sheet l I TN mg mglh J7! @aZZz'more 4, 19490 K. F. GALLIMORE 9 955 RECIPROCATORY DRIVE FOR MACHINE TOOLS Filed July 51, 1944 2Sheets-Sheet 2 jieih 1;; GaZZzlm 02 a 9% WM/ Patented Oct. 4, 1949urnrrno TAT-Es orri .RECIPR'OCAIORgESEFOR :Keith aGallimmi'e, Fond iduLac, Wis, assignor to Giddings .& (Lewis Machine flinch-(10., Fond duLac, 1Nis.,=a=-corp0ration of Wisconsin Application liily 3-1, 1944,"SeriaPNo. 547;4s1

4 8 uGlaims. .1

:present invention melates generally rto :imzprovements inle'ciprocatory drives .ior machine :tools, and has particular reference1012. :new and zirnproved drive orltransmission especially:adapted forStraversingheavy machine'tool omits having :a long range :of movement.

.Onerof :theobjects of :thednvention'is to provide 5a .novelereciprocatory drive for a .machine :tool unit which is-adaptedrtoimpart a uniformmoztion, particularly at the points {f .reversal.

Another object :is :to :provide a mew :and improved drive which 'isadapted ;to impart :2. -balanced:for.ce toithemachine-unit sorasto-avoid zanyltjendency-of the unit tho :IIOCkiCIQSSWiSe Df'the :guidingmeans. 1

.A further object :is :to provide ainovel drive of the ioregoing:character adap.ted to translate the unit over a long range :of movementxwitlmiit :requiring ;a supporting "base of :a length :anpre- :eiably:greater than that :necessary to zaccom- .modate the movement.

.A :general object is to provide :a new and aim- .pr.ov.e.dreciproca-tory :drive zfor Eheavy zmaohine .tool'units whichiissimpleiandinexpensivezin coin struction, -=which is sturdy and :reliablein :opera- :tion, and whichireadilyzadjustable to avary the :rate andrange of movement.

Gther objects and advantages 'will rbecome 'apparent as the descriptionproceeds.

In the accompanying drawings,

Figure 1 is arfront :elevational view ef a amaichineembodying the.features of .my invention.

Fig. 2is-an end elevational viewzof itheimachine.

Fig. '3 [is ran-enlarged fragmentary plan aview ei the :machine,partially :in horizontal section :to illustrate the drive.

Fig. 4 .is a transverse vertical sectional view taken'along line 4-14 of.Fig. 3.

Fig. 5 is a :diagrammatic representation of the drive and :a reversalcontrol therefor.

Referring more particularly to the drawings, the invention :is adapted:for use generally various types of machines jior traversing rh'e'avymachine unitsadjustably over-an extended range of movement. Suchmachines may be adapted to performvarious kindsof-rnetalremovingnperations, such for example asmilling orygrin'din glong surfaces.

The invention is particularly useful :for, and hence shown and described:as embodied :in, a machine :for precision grinding hardened steel waysand otherzsuriacesson large machine units, such for :example as :beds,=jco1umns, tables, saddles, rails, etc. Heretofore, machine 'ways ihavecommonlyabeemfinished byslowzand itedions hand scraping. The pre'sentmachine eliminates these hand operations and their attendantdifficulties by finish grinding the ways or 'other surfaces economicallyand I with a hig'h degree of -accuracy.

'l he :machine'constituting the preferred -em- -bodi'ment Of theirivention comprises an -e'lon- :ga'ted floor plate l adapted 'tosupport :the work to lbe ma'chined- For example, a machine bed=(not-shown having longitudinal way surfaceson =the to'p to Zbe groundniay be supported in stationarypositiomonthe plate The machine-alsocomprises a-stationary base structure having an elongated asubbase 2positioned alongside the il'oo'r pla'te l-, and -'an elox'ig'ated bed4%, preferably ro'f box-type constr'uction, resting on the sub -base andsubstantially coextensive in' length therewith. l ke ibed Z3 is formedonthe top with suitable spaced parallellongituilinalways 4 and 5 forslidably supporting a reci rocame saddle t. In the present instance, theways 4 and 5 .are formed salong the marginal edges of the bed t/Jone way4 ibeingia guiding M -way, and the other way 5 being ia fiat supporting'way. Suitable guards l in the :form @of accordion mellow-s are attachedat :op- :posit'e ends to the ends o'f the bed 3 and saddle 6, ;andserves allzposition's 0f the saddle to en- -c10se1the top-surfacesof thebed to protect the .latter sagainst the entry of foreign matter.

Supportedon'one endof the saddle 5 for movement therewith is a verticalcolumn 8 which preferably is rsquare in transverse construction a ndform'ed with ve'rtic'al guiding means at the ifour :corne'rs. A toolsupporting arm structure .9 1s mounted on therbolumn a for :vertical adjnstment along the guiding means,-and is suitably counterbalanced-andadaptedtote-adjusted manua'lly by operation 'of a -h a'nd wheel LL andto be :cla-mp'edin slectediaoSitiohof adjustment. The :arm -structure9iis form'ed with'oppositely extending :rad ijal overarms M and '92adapted to .be supported selectively in :operative rposition .over ithe'Ifloor plate A! f-or reciprocation wvith the saddie :5 along thesurta'ces .of the workpiece to be frnachined. f-llhe overarm l lsupports a motorized roughing t'tool unit orihead l t-which may corn-.prise 'a-la-rge end face grindin-g wheel lo'cated on a vertical axis.ilviountedronitheother overarm #2 :in laterally :spaced :relation :andsfor indepen' ent adjustment longitudinally offthe arm andalso forangular adaiustment :are two itool :units or heads :M sand 1115. Each ofthe units :55 and 45 comprises awerti'c'al :grin'di'ng spindle 5H5driven by azmotorzll and havingasgrinding-wheel l8 on'the lower :endadapted "to finish grind the -w0rk -surfaces. a

The present invention relates primarily to a reversible translatorydrive for traversing the saddle 6 on the bed 3, and thereby causing thegrinding wheels I8 to traverse the surfaces of the work to be ground. Inthe preferred form, the drive comprises two parallel longitudinal gearracks l9 and 22 mounted in fixed position in the top of the bed 3, anddisposed with their teeth in opposed relation. Two suitable gear pinions23 and 23 are in mesh respectively with the gear racks l9 and 22, andare fixed on the lower ends of two stub shafts 2i and 24 suitablyjournaled in the saddle 3. To avoid tooth interference, the pinions and23 and their shafts 21 and 2d are spaced longitudinally of the saddle 6,and are offset with respect to each other transversely of the saddle.The upper ends of the pinion shafts 2i and 2 extend into a gear chamber25 formed by the webs in the upper portion of the saddle 6 and closed atthe top by a removable access plate 26. Secured respectively to theupper ends of the shafts 2i and 24 within the chamber 25 are two wormgears 21 and 28 in mesh at opposite sides respectively with drivingworms 29 and 30. Preferably, the worms 29 and 33 are of the hourglasstype and formed to provide extensive engagement with the teeth of theworm gears. To permit a close center distance between the shafts 2| and24, the worm gears 21 and 28 are disposed in difierent horizontal planesso as to permit overlapping of their peripheries.

It will be evident that the rack and gear drive for the saddle is simpleand compact in construction. By providing the two rack and pinionassemblies, a strong and balanced drive is obtained. It should also benoted that both rack and pinion assemblies are located in closely spacedrelation to the guiding V-way 4 with the result that during the normaltranslation of the saddle 6, and particularly at the points of reversalof movement, any tendency to rock the saddle crosswise is substantiallyavoided. Preferably, both racks i3 and 22 are mounted in the top of thebed 3 at the inner side of the way 4, but in closely spaced relationthereto. The innermost rack 22 thus is spaced somewhat further than theother rack [9 from the way t, but due to the compact arrangementpermitted by the use of the pinion drive, the racks are located closelytogether and the unequal spacing in relation to the way does not haveany appreciable effect. It is to be understood, however, that the tworacks I9 and 22 might be disposed at and along opposite sides of theV-way if an absolutely balanced relationship should be desired.

The drive worms 29 and 30 are, in turn, fixed respectively on two shafts3| and 32 which extend through the gear chamber 25 transversely of thesaddle 6 and which are suitably journaled in bearings supported in thesaddle web structure. Provision is made for driving the wormssimultaneously in the same direction with a balanced or differentialaction so that both rack and gear assemblies will act jointly and withequal force to drive the saddle 6. In the present instance, a hydraulicdrive is employed, and this drive in its preferred form comprises tworotary hydraulic motors 33 and 34 coupled respectively to the wormshafts 3! and 32. The hydraulic motors may be of any suitable type, suchfor example as type C-Ml made by the Oilgear Company, of Milwaukee,Wisconsin. These motors are of the reversible constant displacementtype, and are flange-mounted on the rear wall of the saddle 6, anddisposed with their operating shafts in axial 4 alinement with anddirectly coupled to the worm shafts 3| and 32.

Any suitable source of fluid under pressure may be provided forsupplying fluid reversibly to the motors 33 and 34. In the presentinstance, the pressure source comprises a rotary pump 35 driven by anelectric motor 36, and having discharge and return sides connected in aclosed circuit through suitable conduits 37 and 38 in parallel to theintake and exhaust sides of the motors 33 and 34. Both the pump 35 andmotor 36 are mounted on the saddle 6 and enclosed in a suitable controlhousing 39.

The pump 35 may be of the type DX-411 made by the aforesaid OilgearCompany. The details or this pump per se form no part of the presentinvention and, therefore, are not fully disclosed herein. It issufiicient to state that the pump 35 has a volume control member 40which is shiftable through a, central or neutral position defining zerodisplacement into opposite limit positions defining respectively presetdisplacements in opposite directions of delivery. The member 40 isoperable under the control of valve means adapted to be actuated bysolenoids M and 42. Thus, when the solenoid 4! is excited, the pump 35will be adjusted to deliver fluid through the line 37 to the motors 33and 34 and receive the return fluid from the motors through the line 38.Consequently, the motors 33 and 33 will operate simultaneously to efiectrotation of the pinions 20 and 23, for example in the direction of thefull arrows (Fig. 5) to translate the saddle 6 to the right. Uponenergization of the solenoid 42, the pump 35 will be reversed to deliverfluid through the line 38 and receive return fluid through the line 31so as to operate the motors 33 and 34 in the reverse direction, andthereby eifect rotation of the pinions 20 and 23, for example in thedirection of the dotted arrows to translate the saddle 6 to the left.When both solenoids are deenergized, the pump 35 will be adjusted intoposition of zero displacement, under which condition the saddle 6 willbe idle. It will be understood that the rate of travel of the saddle 6may be varied by adjustably limiting the operative positions of the pumpcontrol member 40 so that any preset pump delivery in either directionmay be obtained.

By providing two hydraulic motors 33 and 34 of the reversible rotarytype, the use of long 001- umns of fluid tending to result in unevennessof travel is obviated, and the extent of saddle movement in bothdirections is not restricted by any physical limitations of the motors,but can be varied both as to extent and location, restricted only bythe'length of the bed 3. If motors of the cylinder and piston type wereemployed, they would be mounted within and extend longitudinally of thebed, and for a, given maximum length of travel would require the bed tobe provided with a greatly increased overall length.

The two hydraulic motors 33 and 34, being connected to receive fluidunder pressure in parallel from the pump 35, and being connected throughlike parallel gear reduction drives to the rack and pinion assemblies,serve to exercise a differential action so that the pinions will exertsubstantially the same thrust against their respective racks I 9 and 22to share and equalize the load, and at the same time any slightirregularities or unevenness that may be present in the gear teeth ofthe racks and pinions will be compensated for.

Provision is made for effecting automatic re- 'trol housing 39.rotationin synchronism withthetranslation of thei-saddle-fi, and tothisend is driven from the mas es :versal of the pump .35Jto reciprocateltheisaddle 6 through -a predetermined adjustable range.

This means comprisesa rotary control disk 43 mounted on .-a shaftprojecting :from the con- The shaft .44 connected for example 300, fortranslation of the saddle 6 through its maximum range ofmovement.

Adjustably mounted on thelcontrol disk43 are two reversing stops or dogs'49 and 50 adapted for engagement-alternately and respectivelyuponmovement of the saddle 6 in opposite directions with-a switch operatinglever L This lever is .mounted for swinging movement at the rear of thecontrol disk 83 in the path of the dogs 49 and 50, and has an operatingshaft 52 for actuating a limit switch ES controlling theselective-excitation of the valve solenoids 4| and 42.

In operation, at the end of the movement of the saddle 6 in onedirection into one predetermined position, the dog 69 will engage theswitch lever 5! to initiate swinging movement of the latter into oneextreme position, for example as shown in Fig. 5. .A suitableover-center device (not shown) is provided ifor-completin'g the movementof the lever 5i witha snap action. In this position, a circuit iscompleted for the solenoid -42 from a suitable source of electriccurrent through a line 54, one contact 55 of the switch'53, a line 56,the solenoid 42, andaline 5-1. Consequently, the pump adjusting member4%] will be actuated through neutral into one adjustable limitedorpresetpositionlto reverse the delivery of the pump 35 and therebyeffect reversal of the saddle 6. Upon movement of the saddle 5 in theopposite direction intoanother predetermined position, the other dog .59will engage the switch lever 5| to initiate swinging movement of thelatter into its opposite extreme position. The lever 5i thereupon willreverse the switch 53 to deenergize the solenoid 42 and energize thesolenoid M, the circuit being completed from the source through the line54, the contact 58 of the switch 53, a line 59, the solenoid 4 I, andthe line 5'1. Consequently, the pump adjusting member 40 will again beshifted through neutral into its opposite adjustable limit position toreverse the delivery of the pump, and thereby the direction oftranslation of the saddle 6.

With the control as shown, the saddle 6 will continue to reciprocateback and forth and, for each reciprocation, the total head may bemanually adjusted downwardly in a feed increment. To stop thereciprocation when the work surface has been ground to the desireddepth, or for any other purpose, the operator need merely shift thelever 51 into central and neutral position, thereby opening the switch53 and permitting the pump adjusting member 40 to adjust the pump forzero displacement. A positive latching device may be provided forsecuring the lever 5| releasably in stop position.

It will be evident that I have provided a new and improved hydraulicallyactuated reciprocatory drive which is simple and compact inconstruction, and which is sturdy and reliable in operation and adaptedto impart a balanced double thrust to the machine unit to bereciprocated. By arranging the drive in the immediate proximity of theguiding means for the :machine any side thrust against the guiding meansis substantially avoided. Theihydraulic drive provides an equalizing'force :adapted to compensate for any .mi-nor irregularities Iin themechanical gear transmissions so that'the machine unit-is operateduniformly and smoothly. Byemployingrotary hydraulic motors, longcolumnsof fluid under :pressure with their attendant "difficultiesare.avoided,so that thesaddle will be translated :and reversed smoothly.

ll claim: asi-myv invention ,1.. A.reciprocator-y drive .fora;transl-ator machine unit slidable on an elongated bed having alongitudinal guideway, said-drive comprising, in'combination,twoiclosely spaced parallel opositely facingzlongitudinal gearracksmounted on said bedadjacent to and alongside said guide- .way, twovertical shafts ljournaled in said unit and having drive pinions securedthereto and meshing respectively with said racks, two-transverse shaftsjournaled in-and extending crosswise of said unit, worm and worm gearassemblies respectively connecting said transverse shafts to saidvertical shafts, two reversiblerotary hydraulic motors :mounted on saidunit and coupled respectively .to said shafts, a reversible variabledelivery pump mounted on said unit and connected iin a closed circuit inparallel with said motors whereby to rotate said "motors in the samedirection, said worm and-worm gear assemblies *being operable by saidmotors to rotate said vertical shafts relatively in opposite directions,and control means movable in synchronism with said unit and operableautomatically to :reverse the-delivery-of said pump upon movement ofsaid unit respectively in opposite directions into predeterminedpositions of reversal.

2. A reciprocator drive for a translatory machine unit slidable on anelongated bed having a longitudinal guideway, said drive comprising, incombination, :two parallel longitudinal gear racksmountedon saidbedadjacent to andalongside said guideway, two pinion shafts journaledin said unit and having drive pinions secured thereto and meshingrespectively with said racks, two drive shafts journaled in andextending crosswise of said unit, worm and worm gear assembliesrespectively connecting said drive shafts to said pinion shafts, tworeversible rotary hydraulic motors mounted on said unit and coupledrespectively to said shafts, a reversible variable delivery pumpconnected in parallel to said motors, and control means movable insynchronism with said unit and operable automatically to reverse thedelivery of said pump upon movement of said unit respectively inopposite directions into predetermined positions of reversal.

3. A reciprocatory drive for a translatory machine unit slidable on anelongated bed having a longitudinal guideway, said drive comprising, incombination, two parallel longitudinal gear racks mounted on said bedadjacent to and alongside said guideway, two pinion shafts journaled insaid unit and having drive pinions secured thereto and meshingrespectively with said racks, two reversible rotary hydraulic motorsoperatively connected respectively to drive said shafts, and means forsupplying fluid under pressure reversibly and in parallel to saidmotors.

4. A reciprocatory drive for a translatory machine unit comprising, incombination with an elongated bed having longitudinal guide meansthereon, two spaced parallel oppositely facing longitudinal gear racksmounted on said bed adjacent to and alongside said guide means, twovertical shafts journaled in said unit and having drive pinions securedthereto and meshing respectively with said racks, hydraulic motor meansof the rotary type mounted on said unit and peratively connected todrive said shafts reversibly and relatively in opposite directions witha differential action, and means for supplying fluid under pressurereversibly to said motor means.

5. A reciprocatory drive for a translatory machine unit comprising, incombination with an elongated bed having longitudinal guide meansthereon for said unit, two parallel longitudinal gear racks mounted onsaid bed adjacent to and alongside said guide means, two shaftsjournaled in said unit and having drive pinions secured thereto andmeshing respectively with said racks, hydraulic motor means of therotary type mounted on said unit and operatively connected to drive saidshafts reversibly and relatively in opposite directions with adifferential action, and means for supplying fluid under pressurereversibly to said motor means.

6. A reciprocatory drive for a translatory machine unit comprising, incombination with an elongated bed having longitudinal guide means forsaid unit, dual mechanical drive means connected in parallel totranslate said unit reversibly along said guide means, two rotaryhydraulic motors respectively connected to operate said drive meansjointly with a differential balanced action, and a reversible variabledelivery pump connected in parallel in a closed circuit with said motorsto supply fluid under pressure reversibly to the latter and thereby toefiect reciprocation of said unit in opposite directions, and meansoperable in response to movement of said unit into its opposite endpositions to reverse the delivery of said pump.

7. A reciprocatory drive for a translatory machine unit comprising, incombination with an elongated bed having longitudinal guide means forsaid unit, dual mechanical drive means con- '8 nected in parallel totranslate said unit reversibly along said guide means, rotary hydraulicmotor means respectively connected to operate said drive means jointlywith a differential balanced action, and a reversible variable deliverypump connected to supply fluid under pressure reversibly to said motormeans and thereby effect reciprocation of said unit in oppositedirections, and means operable in response to movement of said unit intoits opposite end positions to reverse the delivery of said pump.

8. A reciprocatory drive for a translatory machine element slidable onan elongated bed having a longitudinal guide way, said drive comprising,in combination, two closely spaced parallel oppositely facinglongitudinal gear racks mounted on said bed adjacent to and alongsidesaid guide- Way, two vertical shafts journaled in said unit and havingdrive pinions secured thereto and meshing respectively with said racks,and two drive motors mounted on said unit and operatively coupledrespectively to said shafts to rotate said pinions respectively inopposite directions, whereby the side pressures between said racks andsaid pinions are balanced.

KEITH F. GALLIMORE.

REFERENCES CITED The following references are of record in the file ofthis patent:

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